1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to image processing using least significant bits (LSBs), and more particularly, to an image processing method and apparatus using LSBs of gray code bit-planes or binary code bit-planes.
2. Description of the Related Art
If each pixel value is represented by using a bitstream, most significant bits of the bitstream may greatly contribute to characterize the image. By using such characteristics of images, a bit-plane into which a bit of a predetermined rank of each pixel value is inserted at every pixel position of an image, is used in image processing fields. If a pixel value of an image is represented by using eight bits, the number of bit-planes available for insertion is eight.
FIGS. 1A and 1B are a diagram and a flowchart, respectively, for describing a method of separating n least significant bit-planes 120 from an image formed of N bit-planes 110, according to a related art.
Referring to FIGS. 1A and 1B, if a pixel value is represented by using a bitstream including N bits, a highest-order bit of the bitstream is referred to as the most significant bit (MSB) and a last Nth bit of the bitstream is referred to as the least significant bit (LSB). Thus, when an image is represented by using bit-planes, the image includes the N bit-planes 110 from the MSBs to the LSBs. In the related art, in some cases, only LSBs including the LSB of each bitstream are used. Thus, the n least significant bit-planes 120 are separated from the N bit-planes 110 in operation 150 and are used to process the image.
FIG. 2 is a diagram illustrating bitstreams and bit-planes according to the related art of FIGS. 1A and 1B.
A bit-plane on an image pixel is represented as a binary code.
Referring to FIG. 2, for example, when pixel values of individual eight-bit bitstreams 211 through 217 are 127, 127, 128, 128, 128, 128, and 128, respectively, binary codes 210 corresponding to the pixel values are formed. In this case, bits at a predetermined pixel position of individual binary codes 211 through 217 are arranged on one bit-plane, and if bit-planes including bits 220 corresponding to four LSBs are separated from the binary codes 210, only four-bit binary codes 230 are separated.
However, although the pixel values of 127, 127, 128, 128, 128, 128, and 128 in the binary codes 210 have correlation and similarity with neighboring pixels, if only the four-bit binary codes 230 are separated, individual four-bit bitstreams 231 through 237 have values 15, 15, 0, 0, 0, 0, and 0, respectively, and thus the correlation and similarity with neighboring pixels is reduced.